1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #ifndef _SYS_MUTEX_IMPL_H 28 #define _SYS_MUTEX_IMPL_H 29 30 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 #ifndef _ASM 33 #include <sys/types.h> 34 #include <sys/machlock.h> 35 #endif 36 37 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 41 #ifndef _ASM 42 43 /* 44 * mutex_enter() assumes that the mutex is adaptive and tries to grab the 45 * lock by doing a atomic compare and exchange on the first word of the mutex. 46 * If the compare and exchange fails, it means that either (1) the lock is a 47 * spin lock, or (2) the lock is adaptive but already held. 48 * mutex_vector_enter() distinguishes these cases by looking at the mutex 49 * type, which is encoded in the low-order bits of the owner field. 50 */ 51 typedef union mutex_impl { 52 /* 53 * Adaptive mutex. 54 */ 55 struct adaptive_mutex { 56 uintptr_t _m_owner; /* 0-3/0-7 owner and waiters bit */ 57 #ifndef _LP64 58 uintptr_t _m_filler; /* 4-7 unused */ 59 #endif 60 } m_adaptive; 61 62 /* 63 * Spin Mutex. 64 */ 65 struct spin_mutex { 66 lock_t m_dummylock; /* 0 dummy lock (always set) */ 67 lock_t m_spinlock; /* 1 real lock */ 68 ushort_t m_filler; /* 2-3 unused */ 69 ushort_t m_oldspl; /* 4-5 old pil value */ 70 ushort_t m_minspl; /* 6-7 min pil val if lock held */ 71 } m_spin; 72 73 } mutex_impl_t; 74 75 #define m_owner m_adaptive._m_owner 76 77 #define MUTEX_WAITERS 0x1 78 #define MUTEX_DEAD 0x6 79 #define MUTEX_THREAD (-0x8) 80 81 #define MUTEX_OWNER(lp) ((kthread_id_t)((lp)->m_owner & MUTEX_THREAD)) 82 #define MUTEX_NO_OWNER ((kthread_id_t)NULL) 83 84 #define MUTEX_SET_WAITERS(lp) \ 85 { \ 86 uintptr_t old; \ 87 while ((old = (lp)->m_owner) != 0 && \ 88 casip(&(lp)->m_owner, old, old | MUTEX_WAITERS) != old) \ 89 continue; \ 90 } 91 92 #define MUTEX_HAS_WAITERS(lp) ((lp)->m_owner & MUTEX_WAITERS) 93 #define MUTEX_CLEAR_LOCK_AND_WAITERS(lp) (lp)->m_owner = 0 94 95 #define MUTEX_SET_TYPE(lp, type) 96 #define MUTEX_TYPE_ADAPTIVE(lp) (((lp)->m_owner & MUTEX_DEAD) == 0) 97 #define MUTEX_TYPE_SPIN(lp) ((lp)->m_spin.m_dummylock == LOCK_HELD_VALUE) 98 99 #define MUTEX_DESTROY(lp) \ 100 (lp)->m_owner = ((uintptr_t)curthread | MUTEX_DEAD) 101 102 extern int mutex_adaptive_tryenter(mutex_impl_t *); 103 104 #endif /* _ASM */ 105 106 #ifdef __cplusplus 107 } 108 #endif 109 110 #endif /* _SYS_MUTEX_IMPL_H */ 111